Such a screw has been disclosed by German Utility Model 29812947. This screw is a screw-in plug, although this is a factor which does not change anything with regard to the dimensioning ratios concerning the thread of the screw compared with corresponding simple screws. The known screw is likewise provided in particular for screwing into rigid foam plastic and for this purpose has certain dimensioning of the thread turns with respect to the screw shank. An effect which is desired in this screw consists in engaging behind a large amount of the relevant construction material in order to achieve high retaining forces. For this purpose, the thread is designed as an acme thread in which the thread turns are flattened cylindrically on the outside, so that the thread turns in this case run out in the form of a flat which increases in width in the direction of the screw head. A depth of thread of approximately ¾ of the shank diameter and a thread pitch which approximately corresponds to the shank diameter are specified as especially favorable dimensioning. Values of between 5° and 20° are specified for the thread angle.